Recently, Plasma Display Panel (PDP) has received attention as a large-scale, thin, lightweight display for use in computers and televisions, and the demand for high-definition PDPs has also increased.
Document EP0554172A1 discloses a conventional, typical technique related to a construction and production method of PDP.
FIG. 29 is a sectional view showing a general AC-type PDP.
In the drawing, a front glass substrate 101 is covered by a stack of display electrodes 102, a dielectric glass layer 103, and a dielectric protecting layer 104 in the order, where the dielectric protecting layer 104 is made of magnesium oxide (MgO) (see, for example, Japanese Laid-Open Patent Application No. 5-342991.
Address electrodes 106 and partition walls 107 are formed on a back glass substrate 105. Fluorescent substance layers 110 to 112 of respective colors (red, green, and blue) are formed in space between the partition walls 107.
The front glass substrate 101 is laid on the partition walls 107 on the back glass substrate 105 to form space. A discharge gas is charged into the space to form discharge spaces 109.
In the above PDP with such a construction, vacuum ultraviolet rays (their wavelength is mainly at 147 nm) are emitted as electric discharges occur in the discharge spaces 109. The fluorescent substance layers 110 to 112 of each. color are excited by the emitted vacuum ultraviolet rays, resulting in color display.
The above PDP is manufactured in accordance with the following procedures.
The display electrodes 102 are produced by applying silver paste to the surface of the front glass substrate 101, and baking the applied silver paste. The dielectric glass layer 103 is formed by applying a dielectric glass paste to the surface of the layers, and baking the applied dielectric glass paste. The protecting layer 104 is then formed on the dielectric glass layer 103.
The address electrodes 22 are produced by applying silver paste to the surface of the back glass substrate 105, and baking the applied silver paste. The partition walls 107 are formed by applying the glass paste to the surface of the layers in stripes with a certain pitch, and baking the applied glass paste. The fluorescent substance layers 110 to 112 are formed by applying fluorescent substance pastes of each color to the space between the partition walls, and baking the applied pastes at around 500° C. to remove resin and other elements from the pastes. Japanese Laid-Open Patent Application No. 2-08834 discloses a technique for forming a fluorescent substance film by applying a fluorescent substance slurry then drying the applied slurry by high-temperature dry air.
After the fluorescent substances are baked, a sealing glass frit is applied to an outer region of the back glass substrate 105, then the applied sealing glass frit is baked at around 350° C. to remove resin and other elements from the applied sealing glass frit. (Frit Temporary Baking Process)
The front glass substrate 101 and the back glass substrate 105 are then put together so that the display electrodes 102 are perpendicular to the address electrodes 106, the electrodes 102 facing the electrodes 106. The substrates are then bonded by heating them to a temperature (around 450° C.) higher than the softening point of the sealing glass. (Bonding Process)
The bonded panel is heated to around 350° C. while gases are exhausted from inner space between the substrates (space formed between the front and back substrates, where the fluorescent substances are in contact with the space) (Exhausting Process). After the exhausting process is completed, the discharge gas is supplied to the inner space to a certain pressure (typically, in a range of 300 Torr to 500 Torr).
A problem of the PDP manufactured as above is how to improve the luminance and other light-emitting characteristics.
To solve the problem, the fluorescent substances themselves have been improved. However, it is desired that the light-emitting characteristics of PDPs are further improved.
A number of PDPs are increasingly manufactured using the above-described manufacturing method. However, the production cost of PDPs is considerably higher than that of CRTs. As a result, another problem of the PDP is to reduce the production cost.
One of many possible solutions to reduce the cost is to reduce efforts taken (time required for work) and the energy consumed in several processes that require heating processes.